Editing O2

{{wiktionary|O₂}}
'''O2''', '''O-2''', '''o2''', or similar orthography may refer to:

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==Science and technology==
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* [[Dioxygen]] ({{chem2|O2}}), the common allotrope of oxygen
* [[Oxide]] ({{chem2|O(2-)}}), an ion
* [[Superoxide]] ({{chem2|O2-}}), an ion 
* [[Dioxygenyl]] ({{chem2|O2+}}), an ion 
* [[Doubly ionized oxygen]] ({{chem2|O(2+)}}), an ion
* [[O(2)]], the 2-dimensional orthogonal group in group theory
* O2, an EEG electrode site according to the [[10–20 system (EEG)|10–20 system]]
* [[SGI O2]], a Unix workstation computer
* O2, a class of [[O-type star]]
* [[Orbital O2]], a tidal power turbine in Orkney, Scotland

==Places==
<!-- Do not use subscript for the "2" in these location names; subscript is used only for the logos, not in normal text. According to [[MoS:TM]], you adhere to the best proper English solution in these cases.-->
* [[The O2]], an entertainment district in London, England
** [[The O2 Arena]], the arena within The O2
* [[O2 Arena (Prague)]] or Sazka Arena, an arena in Prague, Czech Republic
* [[O2 Centre]], an indoor shopping and entertainment centre on Finchley Road, London, England
* [[O2 Residence]], a part of the Jumeirah Lake Towers in Dubai, United Arab Emirates
* [[O2 World (Berlin)]], former branding for Uber Arena, an indoor arena in Berlin, Germany
* [[O2 World (Hamburg)]], former branding for Barclays Arena, an indoor arena in Hamburg, Germany
* [[Otoyol 2]], a motorway in Turkey called "O2"
* [[The O2 (Dublin)]], the former name of 3Arena
* [[Ring 2 (Aarhus)]], a road in Aarhus, Denmark, which appears as "O2" on signs
* [[Ring 2 (Copenhagen)]], a road in Copenhagen, Denmark, which appears as "O2" on signs

==Arts, entertainment and media==
===Film===
* [[Oxygen (2021 film)|''Oxygen'' (2021 film)]] or ''O2'', an American-French survival thriller film in production
* [[O2 (2020 film)|''O2'' (2020 film)]], an Estonian-Latvia-Lithuanian-Finnish historical spy thriller film
* [[O2 (2022 film)|''O2'' (2022 film)]], an Indian Tamil language survival thriller film
* [[O2 (2024 film)|''O2'' (2024 film)]], an Indian Kannada language medical thriller film

===Music===
====Albums====
* [[O2 (FireHouse album)|''O<sub>2</sub>'' (FireHouse album)]] (2000) album of the rock band FireHouse
* [[O2 (O-Town album)|''O2'' (O-Town album)]] (2002) album by American boy band O-Town
* [[O2 (Tonéx album)|O<sub>2</sub> (Tonéx album)]] (2002) album by Gospel singer Tonéx
* ''[[O2: Avalon Remixed]]'', a 2002 album by Avalon
* [[O2 (Son of Dave album)|''O2'' (Son of Dave album)]], 2006 album by Son of Dave

====Songs====
* "O2", a song by Orange Range from ''[[Panic Fancy]]''
* "O2", a 2002 song by Sleater-Kinney from ''[[One Beat]]''
* "O2", a song by Suho from ''[[Self-Portrait (EP)|Self-Portrait]]''

===Other arts, entertainment and media===
* [[Ö2]], a radio service for Austria and South Tyrol
* O2, a character in ''[[Kirby 64: The Crystal Shards]]''
* [[UOC O2]], institutional repository of the Open University of Catalonia

==Businesses and organisations==
* [[O2 (brand)]], a global brand name owned by the Spanish telecommunications company Telefónica
** [[O2 Store]], a chain of retail stores owned and operated by Telefónica Europe, with regional subsidiaries:
** [[O2 (brand)]], Telefónica mobile network global brand name
** [[O2 (Ireland)]], merged into Three Ireland
** [[O2 (UK)]], a joint venture with Liberty Global
** [[O2 Czech Republic]]
** [[Telefónica Germany]]
** [[O2 Slovakia]]
* [[O2 Academy]], a chain of music venues
* [[O2 Wireless USA]] or H2O Wireless, a prepaid wireless service by Locus Telecommunications
* [[O2TV]], a Russian independent TV channel

==Vehicles and military==
* [[Cessna O-2 Skymaster]], a military twin-engine light aircraft
* [[Douglas O-2]], a military single-engine observation biplane
* [[O 2-class submarine|''O 2''-class submarine]], a class of submarines of the Royal Netherlands Navy
* [[Oldershaw O-2]], a glider
* [[SP&S Class O-2]], a 1910 steam locomotives class
* [[USS O-2 (SS-63)|USS ''O-2'' (SS-63)]], a 1918 United States O class submarine
* [[GNR Class O2]], a class of British steam locomotives classified O2 by both the GNR and the LNER

===Pay grade===
* O-2, a [[uniformed services pay grades of the United States|uniformed services pay grade of the United States]]:
** [[First lieutenant (United States)]] in the Army, Marine Corps, Air Force, and Space Force
** [[Lieutenant (junior grade)]] in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps

==See also==
* [[02 (disambiguation)]]
* [[Oz (disambiguation)]]
* [[2O (disambiguation)]]
* [[2Q (disambiguation)]] 
* [[Q2 (disambiguation)]]

{{Letter-Number Combination Disambiguation}}